1. Field of the Invention
The present invention relates to a keyswitch, a keyboard including the keyswitch, and an electronic appliance including the keyboard, and particularly to a keyswitch capable of securing a sufficient keystroke while reducing overall surface area of a keyboard base.
2. Description of the Related Art
A conventional keyboard has a keyboard base and a flexible circuit board. The keyboard base is for supporting keyswitches, including an elongated space key. The flexible circuit board is for transmitting electric signals from the keyswitches to other circuitry, for example in a personal computer. The keyboard base is printed with a contact point for each keyswitch and pull-out contacts for the flexible circuit board. Normally, the pull-out contacts are disposed at a position separate from the keyswitches.
Japanese Patent Application Publication No. HEI-7-283504 discloses locating pull-out contacts for the flexible circuit board at the position of the space key. The space key is large compared to other keys. Accordingly, the circuit pattern located at or near the space key is relatively sparse. Therefore, it is relatively easy to design the circuitry pattern on the keyboard base if the pull-out contacts are located at or near the location of the space key.
The flexible circuit board has contact points that overlap with the pull-out contacts for the flexible circuit board. A pressing member with a predetermined stiffness is provided above the flexible circuit board, to apply a uniform pressing force to the overlapping contact points, so that the flexible circuit board is brought into intimate contact with the keyboard base and attached thereto. The flexible circuit board passes through an elongated hole that is formed in the keyboard base at or near the position of the space key.
However, an elongated key, such as a space key, needs to be provided with some sort of guide support member for guiding vertical movement of the key, to ensure that a proper switching operation is performed even if pressure is applied to only one extreme end of the elongated key top. U.S. Pat. No. 6,072,133 discloses such guide support member (actuator) that extends along almost the entire length of the elongated key top, thereby ensuring that switching is properly achieved even if pressure is applied to only one extreme end of the key top.
However, with the configuration of U.S. Pat. No. 6,072,133, space must be provided on the keyboard base for fixing the flexible circuit board to the keyboard base. Therefore, overall surface area of the keyboard base must be fairly large; which increases overall size of a personal computer to which the keyboard is provided.
It is an objective of the present invention to overcome the above-described problem and provide a keyswitch capable of securing a sufficiently large keystroke, while reducing the overall surface area of the keyboard base.